I Energy in Biological Systems A) Energy Needs of all organisms 1) Where does it come from - making and breaking glucose 2) Energy = capacity to do work Light, Heat, Chemical forms 3) Chemicals involved in Energy in Biological systems ATP, Glucose, Enzymes - lower the energy of activation 4) Energy pathway 5) Glucose is made by photosynthesis 6) ATP is made by breakdown of glucose = cellular respiration ATP + X ------- ADP + XP + energy = phosphorylation 7) Energy used in various activities B) Photosynthesis - making glucose and energy for the entire ecosystem 1) Picking apart the reaction a) Light Dependent reaction (Involves ENERGY) Light energy from different wavelengths that make up the light spectrum b) Light Independent reaction (Involves CO2) c) Long term energy storage (Involves Glucose conversion) d) takes place in the chloropasts in the cells of the leaves e) Chloroplast in detail f) Where do gases enter and leave for photosynthesis - stomata of leaves C) Light Dependent - using different wavelengths of light 1) Excitation of chlorophyll and other pigments by light energy (photons) a) different wavelengths of light spectrum carry energy for photosynthesis b) e- move and create energy (ATP) for Light Independent reaction - chemiosmosis c) e- stripped from H2O molecules, O2 is liberated as a gas d) plants have many pigments for capturing light energy, masked by dominance of green chlorophyll, appear during fall - fall foliage spectacle 1) Some sites keeping track of fall foliage Various states Foliage Network U. S. Forest Service Vermont Vermont fall foliage1 Vermont fall foliage 2 Maine Maine foliage State of Maine -fall foliage New Hampshire New Hampshire foliage Weirs Online cam 2) Plants enhance their ability to collect light energy through pigments a) When do we see these pigments - fall foliage D) Light Independent 1) Calvin cycle: uses ATP and three molecules of CO2 attaches to a 3C molecule made from RuBP 2) Leads to the production of 3C molecules, some go back into Calvin cycle, others go to make glucose E) Long term energy storage 1) Glucose=monosaccharide, used to make polysaccharides which are often stored in underground tubers (examples = scroll down to see slides of potatoes, turnips, etc..., or fruits) F) Cellular Respiration - breaking glucose down and using the energy to make ATP (phosphorylation) 1) Relationship between respiration and cellular respiration breathing in oxygen to make water and energy 2) Two step process - Glycolysis, Krebs Cycle (only for aerobic organism G) Glycolysis 1) Initial breakdown of glucose into two 3C pyruvic acid molecules, pyruvic acid dissociates into pyruvate ions 2) Pyruvate has three options depending on whether the organism breathes O2 or not a) Alcohol Fermentation, production of alcohol (ETOH) and CO2 b) Lactic Acid Fermentation, production of lactic acid and CO2 c) Krebs Cycle (see below) H) Krebs Cycle 1) Pyruvate is modified with CoA to make AcetylCoA 2) AcetylCoA enters the Krebs Cycle (2C molecule) into the mitochondrion 3) Becomes attached to a 4C molecule and becomes 6C molecule 4) 6C molecule is gradually broken down into a 4C molecule 5) CO2 is released and e- are taken into the e- transport system 6) Energy for ATP production occurs in the e- transport system 7) Glucose is not the only source of energy used to produce ATP in the Krebs Cycle How other chemicals enter the Krebs cycle
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Copyright © 2001 Jay Pitocchelli. All rights reserved. The contents of this page are the intellectual property of Dr. Jay Pitocchelli for distribution to students enrolled in General Biology BI 01 at Saint Anselm College. These pages may not be copied, photocopied, reproduced, translated, or published in any electronic or machine-readable form in whole or in part without prior written approval of Jay Pitocchelli. Students enrolled in General Biology BI 01 at Saint Anselm College have permission to print this material for their lecture notes. The images linked to this web page are the sole property of Addison Wesley/ Benjamin Cummings Publishers™.
